The invention relates to a locking bolt to be mounted on a support for receiving equipment, e.g. of an electrical or electromechanical nature, more particularly on an aircraft.
Such a locking bolt must permit easy fitting and dismantling of equipment with respect to the support thereof, as well as the plugging in of connectors of the equipment and its support in the case of electrical equipment, particularly when the insertion forces are high. Finally, the bolt must keep the equipment firmly and reliably on the support, even when it is subject to severe mechanical stresses (vibrations, accelerations, shocks), in order to ensure a perfect connection of the electrical equipment.
U.S. Pat. No. 3,212,746 describes a locking bolt incorporating a threaded rod, whereof one end is articulated to the equipment support and to which is screwed a manipulating nut, whose front face is given a cup-shaped configuration and covers a lug fixed to the equipment. This simply designed bolt complies with the above requirements in a satisfactory manner.
Moreover, the bolt described in U.S. Pat. No. 3,212,746 comprises an anti-slackening or release device mainly constituted by a sliding latch carried by the nut and which can be moved between two stable positions, one of which prevents any rotation of the nut on the threaded rod. This anti-rotation device suffers from the disadvantage of requiring action on the part of the operator. When the latter forgets to operate the latch, the anti-slackening device consequently has no effect.
Moreover, the locking bolt described in U.S. Pat. 3,212,746 suffers from the major disadvantage that in the case of an inadequate tightening of the bolt, the equipment may move on its support to a sufficient extent for the lug fixed to the equipment to escape from the cup-shaped slot formed on the front face of the nut.
U.S. Pat. No. 3,282,316 also describes a locking bolt having a threaded rod, whereof one end bears in pivotal manner on an equipment support and a manipulating nut screwed to said threaded rod. The screwing of the manipulating nut to the threaded rod makes it possible to apply a T-shaped part to a lug connected to the equipment. At the end of tightening, balls mounted in said part are applied by springs into openings formed in the manipulating nut, so as to prevent the latter from rotating under the effect of vibrations.
Although the locking bolt described in U.S. Pat. No. 3,282,316 requires no particular action on the part of the operator to prevent accidental loosening or release, like the previously described bolt, it suffers from the disadvantage of not preventing a displacement of the equipment on its support in the case of a poor tightening of the bolt.
The present invention relates to a simply designed, inexpensive locking bolt which prevents an accidental loosening or release without involving any action on the part of the operator and which prevents a displacement of the equipment on its support when the said bolt is inadequately tightened.
According to the invention this object is achieved by means of a locking bolt for an equipment support, incorporating a threaded rod, whereof one end can be articulated to the support, a manipulating nut screwed to said rod and a bearing part mounted on the threaded rod so that it can be applied to a member connected to equipment placed on the support during a rotation of the manipulating nut, characterized in that the bearing part has a predetermined travel with respect to the manipulating nut along the axis of the threaded rod, elastic means being placed between the manipulating nut and the bearing part in order to permanently urge the latter towards said end of the threaded rod in the direction of a front abutment formed on the nut, said elastic means also actuating anti-release means opposing with a predetermined force a relative rotation between the manipulating nut and the bearing part.
As a result of these characteristics, when the locking bolt is tightened, even to an inadequate extent, the bearing part moves away from the front abutment formed on the nut counter to the elastic means over a distance which is sufficiently large for said bearing part to remain in contact with the member linked with the equipment, even if the latter moves away from the nut. Moreover, the presence of anti-release means directly actuated by said elastic means makes it possible to avoid an accidental unscrewing of the nut, without any action being necessary on the part of the operator.
In order to prevent premature wear to the bearing part and the member facing one another and fixed to the equipment, said bearing part is mounted on the threaded rod in such a way as to be immobilized in rotation.
According to a preferred embodiment of the invention, the elastic means comprise at least two compression springs displaced with respect to the axis of the threaded rod and received in recesses formed in the manipulating nut, each spring applying an anti-release member to the rear face of the bearing part having at least two indentations which can be positioned facing said anti-release members.
Advantageously, as the end of the threaded rod is articulated by a spindle on a yoke which can be fixed to the support, a torsion spring is mounted on said spindle and bears on the yoke and on the threaded rod, in order to normally maintain the latter in a setting position inclined by, at the most, approximately 30.degree. in the downward direction with respect to the horizontal.